/// 节流工具（防重复调用）
Function(T) throttle<T>(Function(T) fn, {Duration delay = const Duration(milliseconds: 1000)}) {
  bool enableCall = true;
  return (T args) {
    if (!enableCall) return;
    enableCall = false;
    fn(args);
    Future.delayed(delay, () => enableCall = true);
  };
}